1. Field of the Invention
The present invention relates to optical communication systems, and more particularly to reconfigurable optical network elements.
2. Technical Background
Optical communications systems work by the transmission of light through optical waveguides. Due to the optical properties of the optical waveguides currently in use, only certain portions of the light spectrum are suitable for the transmission of optical signals. Each of these portions of the light spectrum encompasses light from one wavelength to another wavelength, thus defining a waveband. For example the three wavebands of most interest in optical communication systems are the wavebands from 800 nm to 870 nm, 1280 nm to 1330 nm and 1520 nm to 1620 nm. Each of these wavebands may be further divided into multiple sub-wavebands, where each of the sub-wavebands is defined as a region of the light spectrum centered on a center wavelength.
To increase the capacity of optical communications systems, multiple signals are simultaneously transmitted through optical waveguides utilizing the sub-wavebands. Wavelength add/drop multiplexers are an essential element in allowing a single optical waveguide to transmit more than one sub-waveband, and hence more than one optical signal at a time. Wavelength add/drop multiplexers (WADMs) are therefore important elements in optical network applications.
Wavelength add/drop multiplexers either separate a sub-waveband of light from an optical signal or add a sub-waveband of light to an optical signal, or do both. The use of wavelength add/drop multiplexers therefore allows the assembly of a number of discrete signals into a multiplexed optical signal that can travel through a single waveguide to other wavelength add/drop multiplexers where the multiplexed optical signal may be disassembled into its component signals. Each of the component signals may then be introduced into separate waveguides for delivery to different destinations. Wavelength add/drop multiplexers therefore may serve as a basic router in optical communication systems.
Fixed wavelength add/drop multiplexers that manipulate wavelengths do not typically have moving parts to wear out. The absence of moving parts means that fixed wavelength add/drop multiplexers are inherently more reliable than signal routing schemes that rely on switches to deliver optical signals to their proper destinations. One difficulty in using wavelength add/drop multiplexers as routers for optical communication systems has been that they have not been readily reconfigurable. Optical communication system architectures commonly in use do not allow for changing destinations of component signals without the interruption of the multiplexed signal.
The emergence of optical fiber communication systems from xe2x80x9clong haulxe2x80x9d systems into regional and local communication systems means that this lack of flexibility in signal routing without signal interruption must be overcome. This is necessary in order to allow systems to grow to meet customer needs. In particular, emerging metropolitan area network applications will require optical technologies that have low initial installation costs yet allow for optimized growth of the network and deployment of equipment.
To meet these demands, optical systems, components, and the capabilities of network elements ideally should be upgradable. There are a number of important considerations for implementing upgradable technologies. First the technologies ideally should be cost effective. The upgrade should use existing equipment that is in place; in other words, the upgrade should consist of replacing only those components necessary to upgrade capability, not the installation of an entire new suite of components. And most importantly, the upgrades should not interrupt service on wavelength channels that are not serviced by the equipment being upgraded. This last requirement is becoming increasingly important as networks transition from being voice transmission dominated to data transmission dominated. Temporary interruption of data transmission can compromise an entire transmission by introducing errors or requiring the retransmission of the entire message.
To meet the growing demand for upgradable add/drop technologies that meet the above requirements, a unique detachable opto-electronic module system with a simple serial add/drop architecture that allows for in-service upgrades is presented. One application is for upgrading the add/drop capability of a wavelength from fixed, to flexible, to reconfigurable all while maintaining service on unaffected channels. Another application is an upgradable optically protected add/drop card. The card allows service and system providers to customize the deployment of optical layer protection on a wavelength-by-wavelength basis and two change the protection configuration of a wavelength while maintaining service on un-effected channels.
One aspect of the present invention relates to an optical communications device having an optical circuit configured to receive, transmit and manipulate a number of wavebands, and an opto-electronic module, detachably engageable in optical communication with said optical circuit.
In another aspect, the invention may include an optical communication system having an optical circuit configured to receive, transmit and manipulate a number of wavebands. In this aspect, the optical circuit includes a system input port configured to receive the number of wavebands, and an optical processor that separates a waveband from the number of wavebands. The circuit may further include a system output port configured to transmit the number of wavebands from the optical circuit to an optical device docking input port, configured to receive an optical signal from an opto-electronic module, and a docking output port configured to transmit the separated wave band from the optical circuit to the detachable opto-electronic module.
In another aspect, the invention includes an optical communications device having an optical circuit configured to receive, transmit and manipulate a number of wavebands, and an opto-electronic module, detachably engageable in optical communication with the optical circuit. The detachable opto-electronic module includes, an internal input port for receiving the separated waveband from the optical circuit, and a waveguide connecting the internal input port to an internal output port. The output port is configured to transmit the separated waveband from the detachable opto-electronic module back to the optical circuit.
Another aspect of the invention relates to an optical communications device having an optical circuit configured to receive, transmit and manipulate a number of wavebands, and a detachable opto-electronic module engageable in optical communication with the optical circuit. The optical circuit has a system input port, a filter, where the filter separates a waveband from the number of wavebands, a system output port, configured to transmit the number of wavebands from said optical circuit to an optical device, a docking input port, configured to receive an optical signal from the detachable opto-electronic module and a docking output port. The docking output port is configured to transmit the separated waveband from the optical circuit to the detachable optoelectronic module. The detachable opto-electronic module has an internal input port, for receiving the separated waveband from the optical circuit. An external output port transmits the separated sub-waveband from the detachable opto-electronic module to an optical waveguide. An external input port receives an optical signal from a second optical waveguide. An internal output port is configured to transmit the optical signal received from the external input port from the detachable opto-electronic module to the optical circuit.
Another aspect of the invention relates to an optical communication device having an optical circuit configured to receive, transmit and manipulate multiple wavebands. Where the optical circuit has a system input port configured to receive a plurality of wavebands. A filter separates a waveband from the multiple wavebands received. A system output port is configured to transmit the multiple wavebands from the optical circuit to an optical device. A docking input port is configured to receive an optical signal from the detachable opto-electronic module, and a docking output port configured to transmit the separated waveband from the optical circuit to the detachable opto-electronic module. A detachable opto-electronic module, engageable in optical communication with the optical circuit has an external input port, for receiving an optical signal from an optical waveguide. It also has an internal input port, for receiving the separated waveband from the optical circuit, and an internal output port, for optical communication with the optical circuit. A switch directs the separated waveband to either the external output port or the internal output port, where the external output port is for transmitting the separated waveband from the detachable opto-electronic module to an optical device.
Another aspect of the invention relates to an optical communications system having an optical circuit configured to transmit, receive and manipulate a plurality of wavebands. The optical circuit has a system input port configured to receive multiple wavebands and a fiber Bragg grating that separates a waveband from multiple wavebands received. A system output port is configured to transmit the wavebands from the optical circuit to an optical device. The optical circuit also includes a docking input port and a docking output port configured for optical communication with a detachable opto-electronic module.
Another aspect of the invention relates to an optical communications system having an optical circuit configured to transmit, receive and manipulate a plurality of wavebands and a detachable opto-electronic module engageable in optical communication with the optical circuit. The optical circuit has a system input port configured to receive multiple wavebands, a thin film filter for separating a waveband from the multiple wavebands received, and a system output port that transmits the wavebands from the optical circuit to an optical device. It also includes a docking input port for receiving an optical signal from a detachable opto-electronic module, and a docking output port that transmits the separated waveband from the optical circuit to the detachable opto-electronic module.
Another aspect of the invention relates to an optical device for use with an optical communication system. In this embodiment of the present invention, the optical device has an internal input port for receiving optical signals, an internal output port for transmitting optical signals from the optical device to the optical circuit, an external input port for receiving optical signals and an external output port for transmitting the optical signals received from the optical circuit, from the optical device to another optical device.
Another aspect of the invention relates to an optical device for use with an optical communication system. In this embodiment of the present invention, the optical device has an internal input port and an internal output port. The internal input port is configured to receive an optical signal from an optical circuit. The internal input port is one end of an optical path and the internal output port is the other end of the optical path. The optical signal received by the internal input port travels the optical path to the internal output port. The internal output port is configured to introduce the optical signal into the optical circuit.
Another aspect of an embodiment of the present invention relates to an optical device for use with an optical communication system. In this embodiment the optical device includes an internal input port, configured for removable engagement with an optical circuit and capable of communication with the optical circuit. An internal output port, configured for removable engagement with an optical circuit and capable of communication with the optical circuit. An external input port, configured to receive optical signals. An external output port for introducing optical signals into an optical waveguide. A switch for directing the optical signal received from the optical circuit to either the internal output port or the external output port.
The optical communication system of the present invention results in a number of advantages over the prior art. For example, an embodiment of the present invention allows multiple wavebands to be added or dropped from an optical communications systems, without interrupting the transmission of the wavebands not being dropped or added.
Another advantage of an embodiment of the present invention results in the allowance of maintenance of carrying a particular waveband without interrupting other wavebands optical paths being transmitted through the communications node.
Another advantage of an embodiment of the present invention allows the rapid reconfiguration of a system on a channel-by-channel basis, without interrupting the flow of communications carried on separate channels or wavebands, of the optical communications system.
Another advantage of an embodiment of the present invention is the ability to design modular systems using numerous motherboards and detachable opto-electronic modules in diverse combinations to direct large numbers of optical signals contained in separate wavebands coming down single fiber optic cables.
Another advantage of an embodiment of the present invention is the ability of the detachable opto-electronic modules to be configured to provide separate and distinct functions. These functions include reintroducing the signal into the main carrier optical fiber, or taking the separated waveband and directing it towards a remote unit. The detachable opto-electronic module may also incorporate a switch that allows a separated waveband to be directed to a remote unit via the detachable opto-electronic module or to be reintroduced into the optical signal carrying the remainder of the wavebands to another optical device.
Another advantage of the optical communications system of the present invention results in an optical communications device that is capable of directing any number of wavebands capable of being carried on an optical fiber. Each waveband comprising a channel of some form of telecommunications data may be directed to any number of sources without the need for switches. The system is reconfigurable to redirect any of the channels to any other desired location by simply changing the detachable opto-electronic modules, thereby improving the reliability and integrity of the system.
Yet another advantage of an embodiment of the present invention is the economical benefits that are conferred by having an optical communications node capable of having its switching and signal directing capabilities selectively upgradable, without having to invest resources in the redirectable equipment of the node at the time of installation.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from the description or recognized by practicing the invention as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework to understanding the nature and character of the invention as it is claimed.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments of the invention, and together with the description serve to explain the principals and operation of the invention.